All fish dead overnight, inverts fine.

[arowanaman420]

My dad has a 33 long with a golden headed sleeper, lawnmower blenny, clown goby, wheeler's goby some corals, hermits, snails etc. He woke up this morning to find 3 fish and a sally lightfoot dead. The corals, featherduster, hemits and snails are all fine. Also, the pistol shrimp and goby pair survived, but all other fish died. He did a 5g water change last night, the water was mixed 24hrs with the same salt as always. I can't imagine any kind of drastic parameter change from this. My first thought was heater failure, but the temp is still OK. Stray current? But why would the inverts and goby live? I'm baffled so I thought I'd put it to the pros. TIA.

 

[dskidmore]

Have you done any water tests? Could you post the restults?

What is your water topoff and other maintentance routine?

Do you measure the salt by volume, or do you take a salinity reading? Do you use a hydrometer or refractometer? Could the temperature of the mix water have been diffrent than usual? (Temperature affects hydrometer readings, many refractometers self-correct for temperature.)

Do you use tap water or RO?

 

[arowanaman420]

Ammonia and nitrite 0. Nitrate not tested. PH 8.2. Topoff when necessary, w/c 5g every other week. RO water, salinity 1.024 with hydrometer. Temperature was adjusted to match tank water. Again, I can't think of any reason that this particular wc would have caused any dramatic swings, especially negative ones. If that were the case, wouldn't the corals and inverts suffer before the fish?

 

[lando]

Strange indeed. The fact that the inverts are going okay and the fish all died may be the key. in general, inverts are far more sensitive to drastic changes in water chemistry then are fish. This would lead me to focus on some type of disease or infection affecting the fish only. Any visable signs of disease or infection or infestation? All fish eating okay prior to death?

 

[dskidmore]

One invert died though: sally lightfoot.

 

[arowanaman420]

This is what confused me. If it were a fish disease why would the sally lightfoot die? This is what led me to first suspect heater failure or stray current. Still haven't figured this one out.

 

[dskidmore]

Is it possible there was some other contamination involved? Someone put thier hands in the water with perfume/lotion on, or painting going on somewhere else in the house? A small child helping to feed the fishies something they shouldn't have?

 

[arowanaman420]

Definitely a possibility I hadn't considered. My dad does do some auto body work. I'll have to ask him about that.

 

[dskidmore]

Future note, if there's anything with strong vapors in the house, run some fresh carbon that day.